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neural-live electrical-wiring to computer ?

W

w_tom

Jan 1, 1970
0
What was posted was correct. One here should have read
better - or at less told us WHICH wire was at risk for
overload. If he had specifically cited the overloaded wire,
then he would have immediately understood his mistake. But
then he could not misrepresent what was posted.

Two 15 amp device connected to a wall outlet (in US). 30
amps? What is that breaker box (mains panel) circuit breaker
of 15 or 20 amps is doing? Singing the blues? It trips. It
limits current. A 15 amp circuit breaker (or 13 amp fuse in
UK power plugs) makes overload of external power wires not
possible - and informs human of his mistake. 100 devices on a
power strip will create a fire? If too much load for a power
strip, then the power strip 15 amp circuit breaker trips. No
fire. No overload. Those who read before posting learned
repeatedly about a 15 amp circuit breaker so that power cords
could not be overloaded.

What was posted is safe. Not necessarily preferred or
recommended. But one can plug 6 10 amp appliances into a
power strip and not overload wires IF each power strip has
the all so critical 15 amp circuit breaker. What Leonard must
forget to posted insults - the repeatedly stated 15 amp
circuit breaker.

Power strip will not overload because power strip 15 amp
breaker will trip. That is the point. Any extension cord or
power strip that does not have the 15 amp breaker should be
every landlord's concern.

Leonard Caillouet never comprehended what was posted - as
others have noted. Leonard: others had to explain to you
what was posted because again you attack before you
comprehend. Tell us specifically which wire is overloaded.
Explain why the circuit breaker or fuse did not blow. Please
fill us with your wisdom. Yes Leonard, those fuses and
circuit breakers DO limit current through wires. We
specifically put numbers on circuit breakers and fuses so that
current through wires is limited to that number. Why am I
telling you something that even teenagers know?
 
W

w_tom

Jan 1, 1970
0
Even in the UK, things that could cause electronic failure
as posted still apply. Need for computer and printer to share
same safety ground. Need for the AC mains to be properly
earthed. Fact remains - overloaded wall receptacles still do
not cause electronic damage. Even if the tenant had to many
appliances on a wall receptacle, that still does not explain
electronics damage. No matter what size fuses were in his UK
power plugs, electronic failure would not and should not be
created. Fuses do not stop or permit electronic damage. The
tenant complained of electronics failures. The landlord
provided no information that explains that damage.
 
M

Mark D. Zacharias

Jan 1, 1970
0
You're not totally wrong, but you're looking at things much differently. All
of us here have seen and heard where house fires were started by overloaded
outlets, especially where the person (or tenant) did not understand about
electrical current. One hundred devices would not overload a circuit UNLESS
a certain number were actually in operation. A constant 12 amp current draw
might start a fire in a given extension cord, especially because these type
items are often manufactured substandard these days.

In the UK, each device may be limited to 13 amps, but that's no assurance
that several devices operating within their limits would not overload a
given outlet strip. One cannot absolutely trust a circuit breaker. Fuses can
be mislabeled or defeated.

Also, where there's current-flow, any contact resistance generates HEAT. A
loose plug or socket can be frying inside a wall outlet or outlet strip,
even with moderate current flow. If for example, no one were home to see or
smell it, or if a person with disabilities could not correct the situation,
one could return home to a charred pile of rubble.

Once again, we're talking about an unknowledgeable tenant. A friend of mine
had major damage to a rental property because his tenants were stupid this
way.


Mark Z.
 
W

w_tom

Jan 1, 1970
0
How much current must be traveling through a standard 13 amp
UK power cord to cause a fire? Put up numbers. And now how
does all that current pass through a 13 amp fuse without
blowing the fuse. Tenant was not (apparently) blowing fuses.

WE have seen fires due to power cords WITHOUT that all so
essential 15 amp circuit breaker on the power strip. Yes
there are power strips (including surge protector types) sold
without that 15 amp breaker. Shame on them. So and again,
what does the landlord want? He wants his tenants to use
power strips only with the 15 amp circuit breaker (or 13 amp
fuses) so that no overloaded wire can exist. Again because it
is not required and is so important - that 15 amp circuit
breaker on power strip (plug moles).

No blowing fuses or tripping circuit breakers. Even with
numerous items on the power cords, still the current was well
under what could be called overloading. The landlord did not
list amperages from various appliances. He just 'assumed'
multiple appliances meant overloading - an invalid conclusion.

What is the major source of fires in power cords? Not
overloading and especially not if the outlet expanders have
circuit breakers. The major source of such fires is
insulation breakdown. This is also why your Christmas tree
should be powered via an arc fault breaker. Fire due to
insulation breakdown can occur no matter how few plugs are
attached to one receptacle.

Although it will not eliminate these types of fires, the
fuse or circuit breaker would also make those fires less
possible. Fires due to overloading a wall receptacle - not
possible if the plug expander has been properly fused or
circuit breaker. Again, to make any claim of overloading,
first one must say - in detail - which wire is overloaded. No
such claim has demonstrated overloading exists. The overload
accusation is simply speculation.

Why does overloading cause fires? We still permit power
strips and other plug expanders to be sold without the
necessary 15 amp circuit breaker. Do you look at the power
strips your friends use? That was the source of a recent
local fire. But again, power strips (plug moles) did not have
that all so necessary 15 amp circuit breaker. *WE* still
don't demand that circuit breaker be on all plug expanders.
If you consider overloading to be dangerous, then you are
always looking for that 'killer'.

All above is totally and completely irrelevant to the OP's
original post. Landlord did not find a problem even though he
posts as if he did. Every power cord (apparently) was
properly fused meaning no wire could be overloaded. And yet
he still provided no information to explain damaged
electronics. He looked at things totally irrelevant -
suspected overloading, possible wrong size fuses, etc - to
explain electronic damage. False reasoning.

First, although chaining power expanders is not responsible,
still, it could not overload any wire - being as all were
fused. Furthermore, those power expanders do not explain why
the tenant suffered so much computer damage. Reasons for
electronics damage still have not been identified.
Overloading is not the reason for damage and apparently did
not exist - as demonstrated by all those 13 amp fuses that did
not blow.

Lets not forget the #1 target of this discussion. What was
damaging multiple computers and printer? Overloading did not
exist. Fuses were not blowing. And overloading would not
explain electronics damage.
 
L

Leonard Caillouet

Jan 1, 1970
0
Once again, you miss the point of the response and refuse to accept that the
statements that you make might not get the reception that you intended. You
said:

w_tom said:
Most appliances draw hardly any power. One could easily put
four electronic appliances onto the same wall receptacle and
still not even consume 1/4 of what that wall receptacle must
supply. Number of appliances connected to a wall receptacle
is irrelevant as is the fuse in each cord. If all fuses are 15
amps or less, then no overloading is possible.


This is simply incorrect in any country and unsafe advice. The number of
devices is completely relevant. You may have meant something different than
what you stated, but inexperienced readers would easily take this for advice
that could cause big problems.

Leonard
 
J

James Sweet

Jan 1, 1970
0
Also, where there's current-flow, any contact resistance generates HEAT. A
loose plug or socket can be frying inside a wall outlet or outlet strip,
even with moderate current flow. If for example, no one were home to see or
smell it, or if a person with disabilities could not correct the situation,
one could return home to a charred pile of rubble.

My grandmothers house nearly burned down a few years ago from this. The
circuit was not overloaded, but the refrigerator was on the end of a run and
an outlet in the middle devloped a loose connection. The load of the fridge
and the resistance of that outlet caused it to heat up and melt. The
contacts inside the outlet were glowing red when she noticed the coffee
grinder plug fall out of the melting outlet and ran to shut off the breaker.
Replacing the receptacle and trimming back the oxidized wires fixed the
problem.
 
J

James Sweet

Jan 1, 1970
0
w_tom said:
How much current must be traveling through a standard 13 amp
UK power cord to cause a fire? Put up numbers. And now how
does all that current pass through a 13 amp fuse without
blowing the fuse. Tenant was not (apparently) blowing fuses.

WE have seen fires due to power cords WITHOUT that all so
essential 15 amp circuit breaker on the power strip. Yes
there are power strips (including surge protector types) sold
without that 15 amp breaker. Shame on them. So and again,
what does the landlord want? He wants his tenants to use
power strips only with the 15 amp circuit breaker (or 13 amp
fuses) so that no overloaded wire can exist. Again because it
is not required and is so important - that 15 amp circuit
breaker on power strip (plug moles).

What about all the 15A outlets on 20A circuits? It's quite common in the US
anyway, to have a number of 15A outlets on a 20A branch. It's fully possible
to overload the outlet with unfused plug adapters, lots of those out there.
The circuit breakers on power strips aren't of the highest quality either.
 
W

w_tom

Jan 1, 1970
0
Again you post only to argue. Read before posting the
irrelevant. Remember what this discussion is all about? Tell
the OP why overloaded power cords (that could not even blow 13
amp fuses) would cause computer and printer damage. This is
exactly what my previous posts discussed. Somehow you got
totally off on some tangent. Leonard - it really is not so
hard to stay on topic when you want to discuss technically
rather than argue. You posted based only upon what you wanted
to see. Now here is the OP's original problem. How does
overloading not blow 13 amp fuses BUT does cause electronic
damage?

Point one - he had no overloading. Point two - overloading
does not cause electonics damage.
 
W

w_tom

Jan 1, 1970
0
Cited are things totally irrelevant to the OP. Why discuss
"unfused plug adaptors" when there are none? Why even raise
this totally irrelevant issue? Apparently all power cords had
13 amp fuses or equivalent protection. Apparently his loads
were so small as to not even blow those 13 amp fuses.

However what is the expression I keep posting multiple times
in every post? 15 amp circuit breaker on every power strip.
Why are we now discussion a green moon - also known as
"unfused plug adaptors"? Please return to the relevant
topic. Please tell the OP why overloading caused damage to
multiple computers and a printer.

I would not be surprised if someone threw in a discussion of
a refrigerator connected to a defective wall outlet. Why
would speculated and unsubstantiated overloading (that also
could not blow line fuses) cause damage to multiple computers
and a printer?
 
J

James Sweet

Jan 1, 1970
0
w_tom said:
Cited are things totally irrelevant to the OP. Why discuss
"unfused plug adaptors" when there are none? Why even raise
this totally irrelevant issue? Apparently all power cords had
13 amp fuses or equivalent protection. Apparently his loads
were so small as to not even blow those 13 amp fuses.


I don't even know what the OP was about at this point, the discussion has
morphed onto other things.
 
T

Tom MacIntyre

Jan 1, 1970
0
I think what was meant was that the number of devices plugged in does
not matter as long as the total load is kept under the rating of the
circuit (and the rating of any extension cords, power bars, etc.)

Right...people are so busy fighting with this guy all the time that
they don't clearly see what he intends to explain sometimes, but he
doesn't help with his wording either. That being said, the number is
not irrelevant, as, at some point, the limit will be exceeded, even by
a large number of tiny loads, as you explain below..
For example, a normal North American 15A circuit can supply 1 15A
device, 15 1A devices or 100 0.15A devices.

A computer is probably around 600W max, which at 220V (The original post
was from Britain, right?) is a bit under 3A. If the circuit can take
13A you could plug in 4 of those computers without a problem (assuming
nothing else is connected).

600 W sounds high for a PC, to me. I wish I had had more opportunities
to connect PC's to the Sencore (metered) variac where I used to work.
I do recall that some older PC's were typically under 100 W, around
600-700 mA. I know that it is higher today, but if 4 were connected
together, they would be unlikely to be peaking at the same time
either, I'd think.

Tom
 
T

Tom MacIntyre

Jan 1, 1970
0
snip


Reversed Hot and Neutral should not damage computers or any other modern
electronics or appliances, nor is it an inherently unsafe condition.
Anything that plugs into the wall must be designed to be safe if H and N
are reversed.

In isolation yes, but all bets may be off if they connect to another
device which is connected to a correctly phased plug. Been there, got
the T-shirt, saw the lights dim, and smelled the smoke. :)

Granted, when isolated devices are involved, there really shouldn't be
a problem, and nowadays that is usually the case.

Tom
 
M

Mark D. Zacharias

Jan 1, 1970
0
w_tom said:
How much current must be traveling through a standard 13 amp
UK power cord to cause a fire? Put up numbers.

Not possible. Depends on the exact current draw, the exact resistance, the
"heat-sinking" or power dissipation of the load, the presence or
non-presence of combustible material nearby, etc.
And now how
does all that current pass through a 13 amp fuse without
blowing the fuse. Tenant was not (apparently) blowing fuses.

The one device with the 13 amp fuse, as I recall is potentially only one of
several devices on the line.

A single device might start a fire with as little as 4 or 5 watts energy
dissipated in a small enough point with flammable material there. In this
admittedly extreme example, as little as 25 milliamps could start a fire at
220 volts.

All we American tech types are really trying to say is that many people
(tenants, for example) are so unknowledeable in the way they hook up AC
power cords, extension cords, heaters, lamps, etc as to be a hazard to
themselves, others, and in the specific example of the OP, his valuable
rental property.

<snip>

Mark Z.
 
S

Sam Goldwasser

Jan 1, 1970
0
Tom MacIntyre said:
In isolation yes, but all bets may be off if they connect to another
device which is connected to a correctly phased plug. Been there, got
the T-shirt, saw the lights dim, and smelled the smoke. :)

No, not true with anything less than maybe 75 years old.
Granted, when isolated devices are involved, there really shouldn't be
a problem, and nowadays that is usually the case.

Should always be the case unless you have antique radios or something
like that.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.
 
T

Tom MacIntyre

Jan 1, 1970
0
No, not true with anything less than maybe 75 years old.

Sorry, Sam, you should've really paid attention to the "been there"
part...I have had a situation like this arise, and within the past 25
years, with fairly new (at the time) equipment. While attaching a
video cable between 2 pieces of Telidon equipment in 1983, the lights
dimmed, a growling noise occured, and smoke emanated from one of the
units. A meter check revealed that one plug was wired in reverse.

Heck, all you have to do is defeat the capacitor in line with the F
connector on a modern TV set and you'll pop the fuse.

A disturbing aside...I once spoke to an electrician and told him this
story...he said that it didn't matter whether the plug was installed
ground over or under on an AC receptacle, the hot and neutral always
had to each go on the same side. And they don't want us wiring our own
houses...

Tom
 
N

NSM

Jan 1, 1970
0
| Sorry, Sam, you should've really paid attention to the "been there"
| part...I have had a situation like this arise, and within the past 25
| years, with fairly new (at the time) equipment. While attaching a
| video cable between 2 pieces of Telidon equipment in 1983, the lights
| dimmed, a growling noise occured, and smoke emanated from one of the
| units. A meter check revealed that one plug was wired in reverse.

Irrespective, that should never happen. In 1983, no equipment should have
had a hot chassis. The only maker who used to do this (to save the cost of a
power transformer) was Philips who made tube radios and TVs like this and
they went to great lengths to avoid problems. All devices had a well
attached back cover, all pot shafts etc. had sealant applied over the grub
screws and antenna wires were isolated with capacitors.

N
 
T

Tom MacIntyre

Jan 1, 1970
0
| Sorry, Sam, you should've really paid attention to the "been there"
| part...I have had a situation like this arise, and within the past 25
| years, with fairly new (at the time) equipment. While attaching a
| video cable between 2 pieces of Telidon equipment in 1983, the lights
| dimmed, a growling noise occured, and smoke emanated from one of the
| units. A meter check revealed that one plug was wired in reverse.

Irrespective, that should never happen. In 1983, no equipment should have
had a hot chassis. The only maker who used to do this (to save the cost of a
power transformer) was Philips who made tube radios and TVs like this and
they went to great lengths to avoid problems. All devices had a well
attached back cover, all pot shafts etc. had sealant applied over the grub
screws and antenna wires were isolated with capacitors.

N

You are missing the point...once an Abominable Snowman has been
captured and identified, it officially exists. Coelecanth, etc...it
happened, and it happened to me; I witnessed it...therefore, it
exists.

Tom
 
N

NSM

Jan 1, 1970
0
| >Irrespective, that should never happen. In 1983, no equipment should have
| >had a hot chassis. The only maker who used to do this (to save the cost
of a
| >power transformer) was Philips who made tube radios and TVs like this and
| >they went to great lengths to avoid problems. All devices had a well
| >attached back cover, all pot shafts etc. had sealant applied over the
grub
| >screws and antenna wires were isolated with capacitors.

| You are missing the point...once an Abominable Snowman has been
| captured and identified, it officially exists. Coelecanth, etc...it
| happened, and it happened to me; I witnessed it...therefore, it
| exists.

No doubt, but I would certainly have investigated as to how anything wound
up with a hot chassis. Even back then double-insulated was a standard
production methodology. This fault indicates serious and dangerous
mis-wiring (ground to hot)? I might well have contacted the local electrical
safety branch.

N
 
S

Sam Goldwasser

Jan 1, 1970
0
Tom MacIntyre said:
Sorry, Sam, you should've really paid attention to the "been there"
part...I have had a situation like this arise, and within the past 25
years, with fairly new (at the time) equipment. While attaching a
video cable between 2 pieces of Telidon equipment in 1983, the lights
dimmed, a growling noise occured, and smoke emanated from one of the
units. A meter check revealed that one plug was wired in reverse.

Heck, all you have to do is defeat the capacitor in line with the F
connector on a modern TV set and you'll pop the fuse.

A disturbing aside...I once spoke to an electrician and told him this
story...he said that it didn't matter whether the plug was installed
ground over or under on an AC receptacle, the hot and neutral always
had to each go on the same side. And they don't want us wiring our own
houses...

What I said is that equipment must be designed such that this shouldn't
happen, not that a fault couldn't result in the situation you describe.

So, I should have perhaps been more explicit and said 'designed and
manufactured'.

No user accessible part should be connected to H or N directly or via a
low enough impedance to result in an unsafe fault current.

And, not just a plug with reverse H and N - that should still not cause
this. Yes, capacitors can fail. Wires can break loose and short.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.
 
R

RonKZ650

Jan 1, 1970
0
I missed half the thread, and the intended subject, but the fact is it there is
no way in the world reversing the polarity of an AC plug can ever cause voltage
differential between two pieces of equipment. Nope, unless one or most likely
both are hot chassis and both have been tampered with in some way to compromise
the hot chassis safety features such as jumping caps etc. There's a minimum of
about 1meg resistance between hot chassis and any jacks, catv input ect. 1meg
sure isn't going to cause lights to dim or damage regardless of the polarity of
the cords.
 
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